The present invention relates generally to waveform measurement methods, and more particularly to a method for digitally measuring absolute and relative amplitude and time information of electrical signals.
The conventional electronic instrument for general purpose measurement of electrical signals is the oscilloscope, which displays amplitude on the vertical (Y) axis versus time on the horizontal (X) axis. Both the vertical and horizontal axes may be operated either in calibrated or uncalibrated modes. In the calibrated mode, a predetermined amplitude units per distance deflection factor is specified; however, in the uncalibrated mode the deflection factor is variable and therefore cannot be specified with any accuracy.
Modern oscilloscopes have been provided with digital measurement techniques to improve convenience and reduce possible operator error in measuring the display scale. For example, absolute voltage and time measurements have been facilitated using a pair of cursors and a digital voltmeter to read the distance between cursors and provide a readout of the quantity. Heretofore, however, such measurements were accurate only in the calibrated deflection factor modes because the selected scale factor was used to modify the voltmeter reading.